Purpose of App Review
- to explore the robustness of the evidence based practice claim of the app
- to evaluate the user interface
- to assess utility of the app for routine findings or tests
Regardless of the test or findings you use for diagnosing or screening, it is important to understand the statistical limitations of your tools as they will affect the management of your patient. Not only is this consideration critical for controlling rising medical costs, it is also essential to providing good patient care lest we miss a diagnosis because of a test with a low negative predictive value or provide a false diagnosis with a high sensitivity/poor specificity test.
The Evidence Based Primary Care (EBPC) app aims to provide metrics and probability calculations for a large number of laboratory, imaging, symptoms, and physical findings in order to enhance medical decision making.
The home screen for the EBPC app allows you access to all sections of the app. By default it shows you the disease section of the app.
Depending on which option you have chosen, your selection (disease, test, or finding of interest) may lead you to one calculator or multiple calculators.
Once you have chosen the calculator most relevant to your inquiry, you are taken to that calculator’s home screen. All calculator screens are structured the same. The disease of interest is listed on the top with the test or finding listed just below.
The bottom portion of the screen gives the html address to the article used to provide relevant metrics (sensitivity, specificity, predictive values, and likelihood ratios).
The middle portion of the screen shows the important parameters of the calculator.
If you just want to know these parameters, you are done. As an additional feature, you can enter your data to calculate posttest probabilities. After entering the pretest probability, the app calculates your post-test probability for a positive and for a negative result.
For example, I have a patient I am screening for a Chlamydia trachomatis infection. She is in for her annual exam and is younger than 25, so I am screening based on age. She has had a sexually transmitted infection before, so I decide my pretest probability is about 25%. She does not need a pap this year and the patient would prefer to defer a speculum exam.
Should I insist on a speculum exam or can I test her urine?
If I test her urine with PCR and it comes back negative, the probability of her actually having the infection is only 5.36%.
If I obtain the test from the cervix, which has better sensitivity and specificity, that probability is 4.76%.
This difference is minimal and so I decide to screen with a urine sample.
Evidence to support use
- The bottom of each screen lists the paper from which the sensitivity and specificity were taken, complete with its HTML address. It remarks if more than one paper was used or if a meta-analysis was used.
- refers to paper where parameters obtained – truly evidence based practice
- volume of calculators available
- multiple options for looking up calculator
- incorporation of metric definitions
- inability to save favorites
- lack of search function
- does not include important tests for all medical fields
- no embedded links for html addresses
- does not discuss the impact of disease prevalence on predictive values
- lacks ability to compare different tests for same disease side-by-side
Healthcare providers that would benefit from the app
- Useful for any health care providers or health care students interested in knowing important metrics of tests, studies, symptoms, and findings and/or in calculating posttest probabilities.
- The Evidence Based Primary Care medical app provides metrics and probability calculations for a large number of tests, studies, and findings. The app lacks some useful features, but this does not detract from the overall utility and quality of this app.
- The EBPC app is available for the iPad and iPhone. This app is not currently available on the Android platform.
1. User Interface – 3. Sole reliance on back radio button to get back to home screen is a bit clunky and the lack of search or favorites function makes navigating a bit tiresome.
2. Multimedia usage – 4. Easy transitions between screens. Partial split screen display use as well.
3. Price – 4. At just short of a dollar, its cost-effectiveness is excellent.
4. Real world applicability – 4. Helpful for evaluating how a test or test result would influence your management. Might not be used a lot if you are familiar with the tests you are ordering.
App version: 1.1
Compatibility: iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (3rd generation), iPod touch (4th generation), iPod touch (5th generation) and iPad. Optimized for iPhone 5.
Requires: iOs 6.0 or later
Tested on: iPhone 4S
This post does not establish, nor is it intended to establish, a patient physician relationship with anyone. It does not substitute for professional advice, and does not substitute for an in-person evaluation with your healthcare provider. It does not provide the definitive statement on the subject addressed. Before using these apps please consult with your own physician or healthcare provider as to the apps validity and accuracy as this post is not intended to affirm the validity or accuracy of the apps in question. The app(s) mentioned in this post should not be used without discussing the app first with your healthcare provider.